The invention relates to poles for supporting utility lines and more specifically to a hollow tapered pole formed from a plurality of pultruded composite panels.
Presently utility line poles are generally made of wood, steel or concrete. Wood poles are known by the industry to have many existing and long-term problems. These include supply, the use of environmentally questionable treatment such as creosote and pentachlorophenol, and the issue of environmental attack on the life of the pole due to problems with fungus, rot and animal attack. Wood continues to have questions relative to the environmental safety of the preservatives. In some cases, the disposal of the poles has presented questions resulting in unclear direction regarding landfill acceptability and recycling. Existing alternatives include tubular light duty steel poles, which are designed in a twelve-sided configuration, and concrete poles. Both provide equivalent performance to wood, but have significant problems regarding weight, shipping constraints, corrosion and in some cases first costs. Wood appears to be the popular choice of utilities if availability exists due to primarily low initial costs.
In U.S. Pat. No. 5,222,344, the inventor, Johnson, discloses a utility pole having an upper section formed of pultruded composites. In one embodiment, an interior lattice of composite members forms an elongated open celled beam which is enclosed in a preferably composite outer skin.
There are some utility poles utilizing composite processes such as filament winding and centrifugal casting. The drawback to these processes are that they require a mold or a mandrel. Also the maximum height for these type of composite poles appears to be in the 50-55 foot range.
The need for utility poles in the height range of 65-120 feet is presently being served by wooden poles. These poles are quite expensive and the time delay from ordering to delivery is long. Light duty steel poles and concrete poles in this height range are expensive, have long lead times, and are exceptionally heavy.
It is an object of the invention to provide a novel composite pole for supporting utility lines that has a tapered shape.
It is also an object of the invention to provide a novel composite pole for supporting utility lines that in lengths greater than 60 feet are lighter than wooden poles, steel poles or concrete poles.
It is another object of the invention to provide novel composite poles for supporting utility lines that would weigh less than 1000 pounds and thus allow them to be transported by light duty helicopters to remote installation sites.
It is an additional object of the invention to provide a novel composite pole for supporting utility lines that does not have any of the undesirable environmental objections such as are common with the use of timber poles.
It is a further object of the invention to provide a novel composite pole for supporting utility lines that is economical to manufacture and market.